Colloidal silica dispersions have been used for a long time, e.g. as a coating material to improve adhesive properties as well as increasing wear and water resistance of various materials. However, these dispersions, especially highly concentrated colloidal silica dispersions, are liable to gelling or precipitation of silica, which makes longer storage impossible.
English language abstract of JP 3258878 discloses a coating composition prepared by blending an alkoxysilane with a silica sol prepared by reacting a hydrosilicofluoric acid or ammonium salt thereof with ammonia in an aqueous medium, separating formed precipitated silica from the aqueous medium and grinding the precipitated silica in wet state.
It would be desirable to provide a stable and highly concentrated colloidal silica dispersion which can be easily stored and transported without substantial precipitation, even below the freezing point, and that can be used in applications requiring improved adhesive properties, wear resistance, and/or water resistance. It would also be desirable to provide a convenient and inexpensive method of producing such a dispersion. A further object of the present invention is to provide such a stable dispersion which minimises the environmental impact thereof.